I hope that most of my readers are smart enough not to have to be told this, but if you get an authentic-looking, official-looking email from Microsoft telling you to install the attachment with the latest security updates, DON’T DO IT! I’ve gotten a couple of them in the last day or so (and I’m sure my filters have trapped many more).

Never do it. Microsoft doesn’t send security updates out by email–you have to (and should, on at least a weekly basis, apparently) go to their site to do it.